The present invention relates to heat curable siloxane-imide block copolymer compositions and to the tough silicon elastomers obtained therefrom.
Prior to the present invention, one method for improving the toughness of elastomeric polydiorganosiloxanes was the introduction of silphenylene units into the polymer backbone as shown by Sveda, U.S. Pat. No. 2,652,000. Another procedure for improving the toughness of silicon elastomers is by employing either a two component blend, or three component blend of a vinyl containing organopolysiloxane gum having minor amounts of chemically combined siloxy units with at least one vinyl radical attached to silicon, as shown by Bobear U.S. Pat. No. 3,660,345.